Electrohydraulic lithotripsy (EHL) has been an accepted form of therapy for the destruction of urinary stones both in the human bladder and within the individual ureters. Basket extraction of stones is an alternative form of therapy in selected instances. Both urinary stones and biliary stones can be removed by the use of wire basket extraction devices. The choice of the use of either EHL or basket extraction lies in the size and location of the stone, as well as the experience and preference of the urologist. EHL is extremely effective in breaking large urinary stones into pieces small enough for basket extraction or simple passage.
When EHL is selected to affect the destruction of the stone, the EHL probe is placed in close proximity to the stone. By means of an electrical discharge, a shock wave is produced which impacts the surface of the stone and produces tiny cracks. When enough cracks have been made, the stone shatters into small pieces. The individual pieces can then be attacked one at a time, or they can be removed by basket extraction.
Several problems are inherent in EHL. First, EHL is a procedure that requires direct vision to properly place the probe against the stone. And second, there is the danger of perforation of the ureter or bladder during dilation of the ureter orifice or positioning of the cystoureteroscope. The entire time the cystoureteroscope is within the ureter there is also a constant risk of perforation of the ureter.
Further, when the EHL procedure is performed in the ureter, the force of the discharge can propel the stone or its fragments into the delicate lining of the ureter and even perforate the structure. Should the impact point be misdetermined, the discharge of the EHL probe can damage the ureter. Every time the EHL probe fires, the stone moves its position. Therefore, each time the probe is fired, it must be replaced manually on the surface of the stone which is now in a different position. This manual replacement is both time consuming and potentially dangerous.
The device which is the subject of the present invention is designed to combine both a basket extraction device and an EHL probe into a single combination device that will allow a secure hold on a urinary or binary stone while the destructive forces of the EHL probe are used to shatter the stone. The novel combination device of the present invention allows for a safer and faster removal of calculi that was previously not available in the art. Faster, because a single device is used to affect both destruction and extraction of the residual stone fragments, and safer, because this device can be made as small as the smallest wire extraction basket available on the market. In addition, the device of the present invention does not require changing devices in the middle of the procedure, within the very restrictive confines of the urinary or binary tract.
There are a number of prior art references, each of which is directed to some specific discreet element of the system of the present invention; however, none of these references is directed to the totality of the combination, or its use and function in the manner described and claimed herein.
Cecil, U.S. Pat. No. 1,612,697, teaches improvements in instruments for removing and crushing ureteral calculi. In this connection it relates more particularly to the novel arrangement and construction of the parts thereof.
Tessler, U.S. Pat. No. 4,030,505, relates to a method for removing concretions within human ducts, particularly the ureter and kidney, comprising axially abutting a concretion within a human duct, while outwardly distending the walls of the duct adjacent the concretion; generating a series of high voltage electrical pulses of sufficiently low amperage to avoid harm to human tissues; directing said pulses within an insulating medium extending to said ducts to the situs of said concretions; selectively discharging said pulses radially outwardly across the surface of said concretions; and flowing a liquid peripherally of said discharging of pulses, so as to direct a hydroelectric impact against said concretions and within the distended duct walls.
Schwartz et al., U.S. Pat. No. 4,046,150, describes an instrument useful for locating and removing ureteral calculi and other occlusive objects from body passages. The instrument includes a flexible tube or sheath which slidably receives a tightly-twisted multi-stranded cable of a length greater than that of the tube, the cable having an integral cage portion at its distal end. The cage portion, which is normally collapsed and concealed within the distal end of the tube, may be extended beyond the tube to assume an expanded helical pear-shaped configuration for ensnaring and withdrawing ureteral stones and other passage-occluding bodies.
Vasilevsky et al., U.S. Pat. No. 4,203,429, concerns a method of removing concretions from the ureter which comprises passing a concretion from the ureter into the bladder by means of an extractor having a guiding rod at the end of wire arms, crushing the concretion in the bladder by means of a disintegrating instrument, inserting a catheter into the ureter, and removing concretion fragment after the catherization is over.
Rydell, U.S. Pat. No. 4,905,691, is concerned with a polypectome snare whose loop comprises a pair of electrodes mechanically joined but electrically insulated from one another at their distal ends and adapted to be energized by a source of RF voltage for excising polyps on the inside of a body cavity.
Narayan et al., U.S. Pat. No. 5,176,688, teaches an instrument and method for removing stones (calculi) from the kidneys, the bladder and other parts of the body. A stone is captured in a basket at the distal end of an elongated tubular member and broken into pieces while it is held by the basket. The stone is broken up by a hammering action provided by a reciprocating shaft which extends through the tubular member into the basket and is driven toward the stone by a spring.
Essig et al., U.S. Pat. No. 5,397,320, relates to a laparoscopic surgical device which comprises an elongate shaft having a plurality of electrically conductive flexible ribs connected to the distal end of the shaft and to one another to form a cage or basket. Upon placement of an organic body in the cage, the ribs are electrically energized. The organic body is pressed against the ribs to dissect the ribs in a single cauterization operation.